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The present invention relates to a vehicular lamp provided with a plurality of LED light sources, and more particularly to such a vehicular lamp which radiates light using an indirect illumination technique.
Recently, many vehicular lamps have been developed which employ an LED light source. For example, Japanese Patent Application Laid-Open No. 11-306810 discloses a vehicular lamp which provides a soft lighting effect utilizing indirect illumination wherein the LED source is arranged so as not to be visible from the front of the lamp. Further, German Laid-Open Patent Application No. 19638081 discloses a vehicular lamp which is provided with a Fresnel lens as well as an LED light source.
The vehicular lamp disclosed in the above-mentioned German patent application includes a plurality of LED light sources arranged at an upper end portion of the lamp facing downward, and a plurality of LED light sources arranged at a lower end portion of the lamp facing upward. Light from each of the LED light sources is directed downward or upward and formed into a parallel light flux by respective Fresnel lenses provided below or above the light sources, and the parallel light fluxes from each of the Fresnel lens are reflected toward the front of the lamp by a pair of upper and lower reflectors.
By combining an LED light source and a Fresnel lens facing upward, the light from the light source can be effectively utilized. In addition, by arranging a plurality of LED light sources at the upper and lower end portions of the lamp, it is easily possible to make the entire reflective surface have a substantially uniform brightness.
However, by arranging a plurality of LED light sources at the upper end portion and at the lower end portion of the lamp, as in the lamp of the above-mentioned German patent application, there is a problem in that the freedom in designing the outer shape of the lamp is restricted due to limitations in the layout of the LED light sources, the circuit board supporting the LED light sources, and the like.
Taking the foregoing into consideration, it is an object of the present invention to provide a vehicular lamp that radiates light using an indirect illumination technique employing a plurality of LED light sources, and which results in the entire reflective surface having a substantially uniform brightness while enhancing the degree of freedom in the design of the outer shape of the lamp.
The present invention achieves the above and other objects by providing a vehicular lamp having an improved positional relationship between the LED light sources and between the lenses and the reflectors.
A vehicular lamp according to the present invention includes a plurality of LED light sources, a plurality of lenses for forming light from respective ones of the LED light sources into parallel light fluxes, a reflector for reflecting the parallel light fluxes from the lenses toward the front of the lamp, and a translucent cover provided on a front side of the lamp, wherein the plurality of LED light sources are constituted by first and second LED light source groups arranged back-to-back in a row, the plurality of lenses are constituted by first and second lens groups arranged in a row so that the directions of the parallel light fluxes of each of the LED light sources within each group are aligned, that is, the directions of the parallel light fluxes of each of the LED light sources within each group are parallel, and the reflector is formed by first and second reflectors that reflect the parallel light fluxes from respective ones of the lens groups.
Being arranged in a row as used herein means being arranged substantially linearly when viewed from the front of the lamp, with the linear direction of the row not being particularly limited.
The specific structure of the lenses is not particularly limited as far as the lenses can form the light from the LED light sources into parallel light fluxes. For example, it is possible to employ for each lens a single spherical lens, a combination lens, a Fresnel lens or the like.
The reflective surface constituting the first and second reflectors may be formed by a single curved surface or by a plurality of reflective elements.
The direction of the parallel light fluxes mentioned above is not limited to a specific direction as far as the direction intersects the longitudinal direction of the lamp. For example, it is possible to set it to an upward direction or a lateral direction by making it perpendicular to the longitudinal direction of the lamp.
As described above, in the vehicular lamp according to the present invention light from a plurality of LED light sources is formed into parallel light fluxes by a plurality of lenses, and the parallel light fluxes are reflected toward the front of the lamp by a reflector. The LED light sources are constituted by first and second LED light source groups arranged back-to-back in a row, the plurality of lenses are constituted by first and second lens groups arranged in a row such that the directions of the parallel light fluxes in each LED light source group are aligned, and the reflector is formed by first and second reflectors that reflect the parallel light fluxes from respective ones of the lens groups. With this lamp structure, the following operations and effects can be obtained.
Since the first and second LED light source groups are provided in correspondence with the first and second reflectors, it is easily possible for the entire reflective surface of the composite reflector to have a substantially uniform brightness. Further, since the first and second LED light source groups are arranged back-to-back in a row, the first and second reflectors are arranged on opposite sides of the first and second LED light source groups, making it possible to relatively freely select the shapes of end portions of the first and second reflectors.
According to the present invention, therefore, in a vehicular lamp which radiates light by indirect illumination and which employs a plurality of LED light sources, it is possible to cause the entire reflective surface to have a substantially uniform brightness and to enhance the degree of freedom in designing the outer shape of the lamp.
In the structure of the inventive vehicular lamp, the first and second LED light source groups may be mounted on different circuit boards, or they may be mounted on the same circuit board. If the latter structure is adopted, sharing of the circuit board decreases costs of the lamp and makes the light source portion of the lamp compact.
Further, by arranging the first and second LED light source groups in a horizontal direction in the structure described above, the following effects are obtained.
That is, in many vehicular lamps, the outer shape of the upper end portion of the lamp follows the shape of adjacent portions of the vehicle body. Since the first and second LED light sources are arranged in a horizontal direction, the first and second reflectors can be arranged on the upper and lower sides of the LED light sources. Therefore, it is easily possible to make the shape of the upper end portion of the lamp follow the decorative lines of the shape of the vehicle body.
The specific structures of the aforementioned first and second reflectors are not particularly limited. The first and second reflectors may be separated into sub reflectors for each area which the parallel light fluxes from each of the lenses constituting the first and second lens groups strike. In such a case, even if the lenses constituting the first and second lens groups are arranged such that they are displaced from one another in the longitudinal direction of the lamp according to the shape of the lamp or the like, the parallel light fluxes from each of the lenses can be reflected forward with good precision. The first and second reflectors may be integrally formed by a plurality of sub reflectors, or may be formed independently of sub reflectors. Further, the reflective surface of each of the sub reflectors may be formed by a single curved surface, or may be formed by a plurality of reflective elements.
In the structure described above, by further providing a dummy lens portion in the translucent cover, it is possible to prevent the light source portion (that is, the first and second LED light source groups and the first and second lens groups, etc.) from being directly visible when viewed from the front of the lamp. Accordingly, the appearance of the lamp can be further improved. The dummy lens portion, as used herein refers to a lens portion that does not contribute to light distribution control. The specific structure thereof is not particularly limited. For example, an RR (reflex reflector) or a lens portion provided with a decorative pattern may be employed.